Cognitive Load Theory (John Sweller)

This theory suggests that learning happens
best under conditions that are aligned with human cognitive architecture.
The structure of human cognitive architecture, while not known precisely,
is discernible through the results of experimental research. Recognizing George
Miller's information processing research showing that short term memory is limited in the number
of elements it can contain simultaneously, Sweller builds a theory that treats
schemas, or combinations of elements, as the cognitive structures that make
up an individual's knowledge base. (Sweller, 1988)

The contents of long term memory are "sophisticated
structures that permit us to perceive, think, and solve problems," rather
than a group of rote learned facts. These structures, known as schemas,
are what permit us to treat multiple elements as a single element. They are
the cognitive structures that make up the knowledge base (Sweller, 1988).
Schemas are acquired over a lifetime of learning, and may have other schemas
contained within themselves.

The difference between an expert and a
novice is that a novice hasn't acquired the schemas of an expert. Learning
requires a change in the schematic structures of long term memory and is demonstrated
by performance that progresses from clumsy, error-prone, slow and difficult
to smooth and effortless. The change in performance occurs because as the
learner becomes increasingly familiar with the material, the cognitive characteristics
associated with the material are altered so that it can be handled more efficiently
by working memory.

From an instructional
perspective, information contained in instructional material must first be
processed by working memory. For schema acquisition to occur, instruction
should be designed to reduce working memory load. Cognitive load theory is
concerned with techniques for reducing working memory load in order to facilitate
the changes in long term memory associated with schema acquisition.

Application

Sweller's theories are best applied in
the area of instructional design of cognitively complex or technically challenging
material. His concentration is on the reasons that people have difficulty
learning material of this nature. Cognitive load theory has many implications
in the design of learning materials which must, if they are to be effective,
keep cognitive load of learners at a minimum during the learning process.
While in the past the theory has been applied primarily to technical areas,
it is now being applied to more language-based discursive areas.

Example

In combining an illustration of blood
flow through the heart with text and labels, the separation of the text from
the illustration forces the learner to look back and forth between the specified
parts of the illustration and the text. If the diagram is self-explanatory,
research data indicates that processing the text unnecessarily increases working
memory load. If the information could be replaced with numbered arrows in
the labeled illustration, the learner could concentrate better on learning
the content from the illustration alone. Alternatively, if the text is essential
to intelligibility, placing it on the diagram rather than separated will reduce
cognitive load associated with searching for relations between the text and
the diagram (Sweller, 1999).

Principles

Specific recommendations relative to the
design of instructional material include:

Change problem solving methods to avoid means-ends approaches that impose
a heavy working memory load, by using goal-free problems or worked examples.

Eliminate the working memory load associated with having to mentally integrate
several sources of information by physically integrating those sources of
information.